The probability of an attacker catching up from a given deficit is analogous to a Gambler's Ruin problem. Suppose a gambler with unlimited credit starts at a deficit and plays potentially an infinite number of trials to try to reach breakeven. We can calculate the probability he ever reaches ...
That brings us to the heart of this claim, that DHS is using "bad math" in calculating the percentage of positive tests. The MacIver piece itself elaborates on this, asserting, "If the goal is to calculate the daily positive test rate, then DHS is using the wrong numerator ...